path: root/src/kernel/block.c

/*
 * block.c
 *
 *  Created on: Jun 26, 2019
 *      Author: fred
 */


#include "dnbd3.h"
#include "block.h"



static int dnbd3_open(struct block_device *bdev, fmode_t mode)
{
	dnbd3_device_t *dev = bdev->bd_disk->private_data;
	printk(KERN_DEBUG "dnbd3: open device %i\n", dev->minor);
	//TODO can be removed?
	return 0;
}

static void dnbd3_release(struct gendisk *disk, fmode_t mode)
{
	dnbd3_device_t *dev = disk->private_data;
	printk(KERN_DEBUG "dnbd3: release device %i\n", dev->minor);
	//TODO can be removed?

}


void dnbd3_blk_fail_all_requests(dnbd3_device_t *dev)
{
	printk(KERN_DEBUG "dnbd3: fail all requests device %i\n", dev->minor);
}


int dnbd3_net_connect(dnbd3_device_t *dev)
{
	printk(KERN_DEBUG "dnbd3: net connect device %i\n", dev->minor);
	return 0;
}


int dnbd3_net_disconnect(dnbd3_device_t *dev)
{
	printk(KERN_DEBUG "dnbd3: net disconnect device %i\n", dev->minor);
	return 0;
}

static int dnbd3_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg)
{
	int result = -100;
	dnbd3_device_t *dev = bdev->bd_disk->private_data;
	char *imgname = NULL;
	dnbd3_ioctl_t *msg = NULL;

	printk(KERN_DEBUG "dnbd3: ioctl device %i, cmd %i, arg %lu\n", dev->minor, cmd, arg);
	//unsigned long irqflags;

	while (dev->disconnecting) {
		// do nothing
	}

	if (arg != 0) {
		msg = kmalloc(sizeof(*msg), GFP_KERNEL);
		if (msg == NULL) return -ENOMEM;
		if (copy_from_user((char *)msg, (char *)arg, 2) != 0 || msg->len != sizeof(*msg)) {
			result = -ENOEXEC;
			goto cleanup_return;
		}
		if (copy_from_user((char *)msg, (char *)arg, sizeof(*msg)) != 0) {
			result = -ENOENT;
			goto cleanup_return;
		}
		if (msg->imgname != NULL && msg->imgnamelen > 0) {
			imgname = kmalloc(msg->imgnamelen + 1, GFP_KERNEL);
			if (imgname == NULL) {
				result = -ENOMEM;
				goto cleanup_return;
			}
			if (copy_from_user(imgname, msg->imgname, msg->imgnamelen) != 0) {
				result = -ENOENT;
				goto cleanup_return;
			}
			imgname[msg->imgnamelen] = '\0';

			printk(KERN_DEBUG "dnbd3: ioctl image name of len %i is %s\n", (int)msg->imgnamelen, imgname);
		}
	}

	switch (cmd) {
	case IOCTL_OPEN:
		printk(KERN_DEBUG "dnbd3: ioctl open\n");
		if (dev->imgname != NULL) {
			result = -EBUSY;
		} else if (imgname == NULL) {
			result = -EINVAL;
		} else if (msg == NULL) {
			result = -EINVAL;
		} else {
			if (sizeof(msg->host) != sizeof(dev->cur_server.host)) {
				printk(KERN_INFO "dnbd3: odd size bug#1 triggered in ioctl\n");
			}
			memcpy(&dev->cur_server.host, &msg->host, sizeof(msg->host));
			dev->cur_server.failures = 0;
			memcpy(&dev->initial_server, &dev->cur_server, sizeof(dev->initial_server));
			dev->imgname = imgname;
			dev->rid = msg->rid;
			dev->use_server_provided_alts = msg->use_server_provided_alts;
			// Forget all alt servers on explicit connect, set first al server to initial server
			memset(dev->alt_servers, 0, sizeof(dev->alt_servers[0])*NUMBER_SERVERS);
			memcpy(dev->alt_servers, &dev->initial_server, sizeof(dev->alt_servers[0]));
//#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
//			if (blk_queue->backing_dev_info != NULL) {
//				blk_queue->backing_dev_info->ra_pages = (msg->read_ahead_kb * 1024) / PAGE_SIZE;
//			}
//#else
//			blk_queue->backing_dev_info.ra_pages = (msg->read_ahead_kb * 1024) / PAGE_SIZE;
//#endif
			if (dnbd3_net_connect(dev) == 0) {
				result = 0;
				imgname = NULL; // Prevent kfree at the end
			} else {
				result = -ENOENT;
				dev->imgname = NULL;
			}
		}
		break;

	case IOCTL_CLOSE:
		printk(KERN_DEBUG "dnbd3: ioctl close\n");
		dnbd3_blk_fail_all_requests(dev);
		result = dnbd3_net_disconnect(dev);
		dnbd3_blk_fail_all_requests(dev);
		set_capacity(dev->disk, 0);
		if (dev->imgname) {
			kfree(dev->imgname);
			dev->imgname = NULL;
		}
		break;

	case IOCTL_SWITCH:
		printk(KERN_DEBUG "dnbd3: ioctl switch\n");
		result = -EINVAL;
		break;

	case IOCTL_ADD_SRV:
	case IOCTL_REM_SRV:
		printk(KERN_DEBUG "dnbd3: ioctl add/rem srv\n");
		if (dev->imgname == NULL) {
			result = -ENOENT;
		} else if (dev->new_servers_num >= NUMBER_SERVERS) {
			result = -EAGAIN;
		} else if (msg == NULL) {
			result = -EINVAL;
		} else {
			memcpy(&dev->new_servers[dev->new_servers_num].host, &msg->host, sizeof(msg->host));
			dev->new_servers[dev->new_servers_num].failures = (cmd == IOCTL_ADD_SRV ? 0 : 1); // 0 = ADD, 1 = REM
			++dev->new_servers_num;
			result = 0;
		}
		break;

	case BLKFLSBUF:
		printk(KERN_DEBUG "dnbd3: ioctl blkflsbuf\n");
		result = 0;
		break;

	default:
		printk(KERN_DEBUG "dnbd3: ioctl unhandled cmd\n");
		result = -EIO;
		break;
	}

cleanup_return:
	if (msg) kfree(msg);
	if (imgname) kfree(imgname);
	return result;

}



struct block_device_operations dnbd3_fops =
{
	.owner = THIS_MODULE,
	.open = dnbd3_open,
	.release = dnbd3_release,
	.ioctl = dnbd3_ioctl,
	.compat_ioctl =	dnbd3_ioctl,
};